MiniMax H3 Prompt Guide

Purpose

Short prompt-authoring companion for the maintained MiniMax H3 r2v master. This keeps the prompt shape close to MiniMax's official H3 docs while matching the local ComfyUI workflow that Chris is actually using.

Bundled default Subject 1 character reference image: references/default-character-reference.jpg

Bundled default location reference for <Picture 1>: references/default-location-reference.jpg

Optional provenance note for that location reference: references/default-location-reference.url

Official MiniMax doc takeaways

Based on:

https://platform.minimax.io/docs/guides/video-generation
https://platform.minimax.io/docs/guides/video-prompt
https://platform.minimax.io/docs/api-reference/video-generation-v2-h3-context-ir

Key points worth preserving:

Every request needs one non-empty text prompt.
reference-to-video can combine reference_image, reference_video, and reference_audio.
Official H3 limits allow up to 9 reference images, 3 reference videos, and 3 reference audio clips, with mixed inputs capped at 12 files total.
Prompt length limit is 7000 characters.
Official duration is 4-15 seconds, but this local workflow should still be planned around one clean 10s beat per generation block.
Local corrected-reference testing on 2026-08-22 showed this maintained workflow completing through 17s on the current 8 GiB machine, while 20s failed with GPU out-of-memory. Treat 17s as the verified local ceiling for this exact setup, not a universal MiniMax limit.
MiniMax explicitly recommends describing the relationship between references, not just listing disconnected visual details.
Camera guidance can be embedded directly in the prompt; their docs call out tags like [pan], [zoom], and [static] as valid simple controls.
H3-Context-IR exists to expand multimodal input into a richer structured prompt, but the current ComfyUI workflow still benefits from a clean manual prompt shape.

Local workflow rules

Treat <Picture 1> as the environment / master-scene reference when an environment reference is used.
Use references/default-location-reference.jpg as the default <Picture 1> location reference until a shot-specific environment image replaces it.
Treat references/default-character-reference.jpg as the default file to load into <Picture 2> when you need a starter Subject 1 full-body reference and have not chosen a different one yet. Duplicate that same file into <Picture 3> when you want a face-reinforcement slot but only have the single bundled starter identity image available.
Group all images belonging to the same character explicitly.
State what each reference controls and what it must not control.
Ignore the backgrounds of character references unless a reference is explicitly assigned as the environment.
Keep one coherent action beat per 10s block.
End each block in a state that naturally feeds the next continuation shot.
If you need the safest local duration target, stay at 12s or below; use 17s only as the tested upper bound for this box.

Recommended prompt order

Use this order for the actual text block:

Reference assignment
Reference usage and conflict resolution
Shot description
Camera
Visual continuity
Dialogue
Audio

That order matches both the official MiniMax emphasis on relationship-aware multimodal prompting and the authority rules already captured in the local workflow.

Prompt-writing rules

Start by declaring which pictures belong to which subject.
Say which image owns environment, body, face, clothing, props, or product identity.
Tell the model what to ignore from each reference.
Describe the shot chronologically.
Keep camera language simple and continuous.
Keep dialogue short enough to fit inside the same motion beat.
State ambience and sound effects plainly instead of over-scoring the audio.

Copy style that works well

Preferred reference phrasing:

<Picture 1> is the environment and master scene reference.

<Picture 2> and <Picture 3> both represent Subject 1.
<Picture 2> is the primary full-body reference for Subject 1.
<Picture 3> is the facial identity reference for Subject 1.

Use <Picture 1> to define the environment, layout, lighting, and composition.
Use <Picture 2> to define Subject 1's body proportions, hair, and clothing.
Use <Picture 3> to reinforce Subject 1's face.

Ignore the original backgrounds of character references.
The environment is defined only by <Picture 1>.

Preferred shot phrasing:

Shot 1 - 0.00s-10.00s

Subject 1 stands near the shop counter facing three-quarters left.
Subject 2 enters from the right edge and slows beside the doorway.
Subject 1 looks up, turns towards Subject 2, and gives a restrained nod.
Subject 2 answers with a small smile and steps closer.
The action ends with both subjects holding position, leaving the conversation
open for the next extension.

Preferred camera phrasing:

Camera: medium-wide eye-level two-shot, slow push in, no cut, no sudden
reframe. [static] at the start, then a gentle [push in] as Subject 2 enters.

Preferred audio phrasing:

ambient_sound: quiet interior room tone, distant refrigeration hum, soft street
noise outside
sound_effects: light footsteps, fabric rustle, door handle click
non_diegetic_music: N/A

Avoid

Re-describing the whole environment when <Picture 1> already establishes it
Treating multiple references of one person as separate people
Stacking several unrelated actions into one 10s block
Long monologues inside a movement-heavy shot
Overcomplicated camera choreography
Mixing environment authority between the master scene and character images

Recommended workflow use

Use prompt-template.md as the starting copy block.
Use custom/chris/minimax-h3-extender-working/prompt-set-specification.md when building a full multi-shot extension plan.
Use optimized/notes/minimax-h3-ref2va-prompt-guidelines.md when you need the longer rationale behind reference authority and local-safe constraints.

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